Method of making portland cement



Nov. 17, 1931 A. c. EICHENLAUB ET AL METHOD OF MAKING PORTLAND CEMENT Filed Jan. '7, 1927 Patentedv Nov. 17, 1931 ADELBERT C. EICHENLAUB AND' HERMAN SIGNORS OF ONE-THIRD T CONRAD C. MILLER,

e. Losanna, or Das Momes, Iowa, As-

or DES MOINES, Iowa METHOD OF MAKING' PORTLAND CEMENT Application led January 7,

'The principal obj'ect of our invention is to dry the slurry and cool the clinker by means of each other in a single operation.

More specifically theobject of our lnven- `tion is to dry the Portland cement slurry and Acool the'Portland cement clinker by passing the hot clinker through a cooler mounted inside a rotary dryer through which the slurry is slowly passing.

'. increase production.

l and. illustrated inns, in which drying of the 'slurry clinkers. ISlurry consists of an intimate mixsequentl f mixing Ituremust be dried and placed in'a kiln to -to incipient fusion ofthe slurry A- further obj ect is to simplify the machinery for making Portland cement and. also A further object is to reduce the amount of fuel now being used to manufacture Port- `land cement.

A still further object-is to increase the temperature in the stack and the placing of Water tanks' in said A still further object is todrawair through the rotary cooler and then through the rotaryA dryer.

These and other objects will be apparent to those skilled in the art.`

. Our invention consists inthe method here-l inafter set forth, pointed out in our claims in the accompanying draw- 1g. 1 is'a diagrammatical side viewof the machinery used inour improved method of making Portland cement, A

'Fig. 2 is a cross sectional view of the ro- .tary cooler and dryer and is taken on line 2 2 of Fig.1.

Two of the big manufacturers of Portland cement are the and the cooling of the containing ordinarily fromthirty to thirty-f five percent of water. This-Water is picked up when the materials are mixed with Water for grinding to the desired' fineness, or as in A the dry process, the grinding of the materials in a .drystate'to'the desired Iineness, and subwith Water. This Wet mixproduce the 'clinken The clinker is therefore the material produced by the calcination and leaves utilizing the heat 1n stack for supplying hot Water to the ball mills. f

problems that confront i dried. We have 1927. vSerial No. 156,044.

the kiln at a temperatureof about 12,100 degrees Fahrenheit. Many methods are used for cooling the clinker, such a.. leaving 'the same in an open field to cool off naturally, immersing in water, subjecting to`air currents in rot-ary cooling shells', and the like, but in each of these methods, the cooling involves. a total loss of heat units. of the slurry demands a greatamount of fuel. It has been tried to draw the heated products of combustion from the stack over the slurry butthis'contaminates the same due to the presence of furnace gases.

l e have overcome vthese disadvantages by the clinker `to dry the slurry. A

We have used the numeral 10to designate the kil-n. It isa long steel plate cylinder ca able of 'slow rotation with the-delivery end set slightly lower than th'e feed end, so that the material will slowly pass to the delivery end. If the slurry is placed in the feed end The drying of the kiln in wet condition it commences at f once to dry in that end of the kiln to a sermdry substance, thereby Vshrinking involume. From this zone the semi-'dry material passes toward the lower end of the kiln and reaches the burning' zone where the temperature .of

the kiln and materials4 is 'raised to thepoint of incipient 'fusion and clinker results. From the delivery .end o f the kiln the hot clinker passes through a spout 11 Yinto the delivery end=of our cylindrical coolin shelll 12'.. This cylindrical shellis mounte concentricvally inside the rotary drying shell 13 capable of slow rotation. It is in this last mentioned shell that part of the'slurryxis used the numeral 14 to designate a ball mill having the feed pipe`15. From this mill the Wet slurry passes intol the outlet pipe 16. -From testsxwe find that the v clinker only possesses enough British thermal units to reduce the water in the slurry onehalf., or leaving about seventeenpercent in the slurry. We therefore find that it is easier to handle the slurry,

which'is capable of .completely drying a part Therefore by'only passing a part` of the same through the drying cylinder,

in the drawings we show part of the slurry passing through the pipe 17 into the dryer 13 and the other part going directly to'jthel kiln by an elevator or other suitable means. In the drawings we merely show it inthe form of an auger conveyor 18. The delivery end of the cooler and dryer, the same as'the kiln, is at a lower altitude than the feed end, and for this reason the clinker and slurry slowly work toward the delivery end.

Lifting plates 19, fastened to the inside of the outer shell 13, run parallel to t-he aXis of the dryer for its entire length. The revolving i l of the dryer causes these plates to lift and drop the material being dried onto the hot inner shell 12. It will be found that less power is necessary to rotate this type of dryerthan the single shell dryer due to the fact that a large portion of the slurrry lies on top of the inner shell and is carried over the center be fore being a ain dropped to the outer shell; the center o gravity of the slurry being not far from the axis of rotation. The lifting plates 20 in the inner shell tend to hold the clinker close to the inside of the shell.- We have' provided an air inlet port 21 so that air may pass through same into the shell 12 and through the 'cascading clinkers being cooled. From the end of the shell 12 which terminates inside the outer shell 13, the air which has absorbed much heat from the clinker passes back in the annular space between the two cylinders, coming into intimate contact with the showering material to be dried.

This course taken by the air is provoked by an induced draft fan 22. By this arrangement andthe feeding of the slurry at the head end' of the shell 13, the wet material comes in contact first with the greatest heat and still has the counter-current principle of the hot air traveling against the material being dried.

- Any suitable means may be used to rotate the kiln and cooler and dryer shells. The` dry slurry will pass through holes 23 in the end `of the shell 13 and may be .conveyed to the kiln in any suitable manner. In the drawings we merely show an auger conveyor 24. The cold clinkers pass through the holes 25 in the end of the shell 12 andto a mill, not shown. By much of the slurry'entering the kiln in dried condition, the kiln does not have to be near as long as the ones now in use. The slurry is more readily in condition for the burning zone and because of this condition is also -more rapidly converted into clinker, thus increasing'the production of the plant.

It will readily be seen bythose skilled in the art, that the fuel cost will be reduced enormously, while the stack temperature will be greatly increased. v

If it is desired boilers or tanks 26 may be placed infthe stack 27. By using hot water inthe ball mill from these tanks, it will bey found that the slurry will enter the drying shell and the kiln in very hot condition.

rotary cooler, lifting plates may be secured to'the outside of the cooler. Any desirable method for operatively connecting thevball mill, clinker kiln, rotary dryer, fan 22, and

rotary augers 18 and 24 to a prime mover may be employed.` v

In actual practice we recommend the pipe 16 leading to a storage tank and a separate pipe leading from the 'storage tank to the pipes 17 and 18 so that the slurry may beobtained as desired.

It will readily be understood by those skilled in the ,art that we have utilized every possible heat unit and thereby increased the thermal efliciency and decreased the fuel cost.

IVe claim as our invention:

1. The method of making Portland cement which comprises subjecting dried'slurry to such a temperature inside a kiln as to produce cement clinker, passing the heated clinker through an enclosed passageway, passing the raw cement slurry before yit reaches the kiln through a passageway surrounding the enclosed passageway through which the hot clinker passes whereby the clinker is cooled said dried slurry into the kiln.

`3. The method of making Portland fcement which consists. in subjecting dried `clinker passes whereby the slurry is driedby i indirect contact with the clinker and passlng slurry to such a temperature inside the kiln i as to produce cement clinker, passing the heated clinker through an enclosed vpassageway, passing the raw cement slurry through a passageway surrounding the passageway through which the hot clinker passes, passing air first through the passageway through' which the hot clinker passes and then through Y the passageway through which the slurry` passes wherebycooling the clinker and dry-y ing the slurry and finally passing the dried slurry into the kiln.

ADELBERT C. EICHENLAUB. HERMAN G.` LOKEFFLER., 

